Presser foot



Sept. 6, 1949 F. P. TAMBURRO PRES SER FOOT 3 Sheds-Sheet 1 Filed Feb.28, 1944 INVENTOR j mflvis P Tamurro ATTORNEYS Sept. 6, 1949. F. P.TAMBuRRo PRES SER FOOT 5 Sheets-Sheet 2 Filed Feb. 28, 1944 lNyENTORliramcw]? Tamburm,

ATTORNEYS Sept. 6, 1949. F. P. TAMBURRO PRESSER FOOT 3 Sheets-Sheet 3Filed Feb. 28, 1944 ATTORNEYS Patented Sept. 6, 1949 PRESSER, FOOTFrancis P. Tamburro, Ozone Park, N. Y.. assignor to Willcox & GibbsSewing Machine Company, New York, N. Y., a corporation of New YorkApplication February 28, 1944, Serial No. 524,159

8 Claims. (Cl. 112- 235) This invention relates to sewing mach nes, andmore particularly to machines adapted to stitch together the edges offabric sections and the like to form felled seams.

An object of this inventon is to provide an improved presserdevice whichis so articulatedand controlled that it functions to maintain a closecontrol of the material at the felled seam regardless of wide variationsin the thickness and size of said seam, as caused by the meeting andinterfolding of cross-seams in the material.

This is accomplished by a novel mounting of a front presser foot and arear presser foot in tandem for pivotal and translational movementwhereby thepivots are so located with respect to each other and to thework that movement of the presser feet in riding over cross-seams in thework is in a direction which has no component opposing the feedingmovement of the work. As a result, a uniform and positive work feed isobtained.

When joining fabric sections which have felled cross-seams by sewing thesections together using a felled scam, I have found that the mostdifficult condition for feeding and sewing arises when the fabricsections are arranged so that theleading ro llof the cross-seams is onthe top of the sections where it will contact the front presser footahead of the rest of the cross-seam, such contact usually being abruptand having a certain amount of impact, especially when the speed of thework feed is substantial.

- It is another object of the present invention to provide an improvedpresser device which functions to effect apositive work feed regardlessof whether the roll of the cross-seams onthe top surface ofthe work isleading or trailing as the seam approaches the presser feet.

This is accomplished by providing an auxiliary pressure means associatedwith the rearpresser foot and functioning independently of the pressureof the presser bar of the machine but augmenting the latter whereby thepressure on the work of the front foot and the rear foot, has a relationwhich results in a uniform feeding of :the cross-seams past the sewingmeans of the machine.

A feature of the invention is the provision of an improved materialcontrol means as above which may be readily adapted to existing machineswith but little change being required. 1

Another feature of the invention is the .provision' of means as abovewhich are simple to manufacture and reliable in operation.

. Other features and advantages will hereinafter appear. r In theaccompanying drawings- .Figure 1 is a fragmentary side elevation of amachine embodying the invention.

Fig. 2 is a fragmentary side elevation of the material control means ofthe invention, showing the tandem-arranged presser feet in loweredposition, and showing felled cross-seams approaching same. I

Fig. 3 is a similar view showing the action of the presser feet asv thecross-seams begin to engagethe forward foot. y

Fig. 4 shows the action of the presser feet as the cross-seams reach thepivot point of the forward foot. s

Fig. 5 shows the position of the. feet when the cross-seams are justpast the pivot point of the forward foot, and beginning to engage therear foot.

Fig. 6 shows the position of the feet when the cross-seams are raisinthe front part of the rear foot.

Fig. '71s a view like Fig. 2 but partly in section, andshowing therelative positions of the feet as the cross-seams reach the pivot pointof the rear foot.

Fig. 8 is an exploded view of the improved tandem presser-feet control.

' Fig. 9 is a vertical section taken on the line 9-9 of Fig. 2.

Referring; to Fig. 1, a sewing machine embodying the present inventionis shown as having a supportingarm 12- extending in a lateral directionto. cooperate with a sewing head 13 which supports the presser. bar andneedle operating mechanisms of the machine. Needles M are mounted forreciprocating movement in the usual manner, and cooperate with loopers(not shown) in the work-supporting arm 12 for .stitching work,-which maycomprise fabric sections and the like, fed over the arm. As shown inFig. 2, feed dogs l5 are provided to feed the work [6 past the needlesI4, said dogs beingmounted for fourmotionmovement in the arm l2 andhaving teeth extending through apertures in a throat-plate l1.

feller or interfolder i8, Fig. 1, is located on the arm l2 ahead of theneedles [4 for automatically interfolding the edges of the fabricsections in advance of the needles to be joined by thestitching. Asshown, the feller I8 is of the type adapted to handle sections havingfelled cross-seams whereby the latter as they are made to meet or alignare interfolded at their ends in the same manner as the rest of theedges making up the seam.

. .The machine shown may be of the type oommercially-well known astheWillcox and Gibbs SewingMachine Company's Feldlock Machine, asillustrated in Patent No. 1,796,111, issued to G; M. Lewis March 10,1931.

Accordingto the present invention, for controlling the felled edges ofthe work it after they leave.the feller 18, there is providedan'improved presser means cooperating with the feed dogs l5 and.throat-plate l1 so as to cause the felled the thickness of the seam maybe of considerable magnitude, since as shown in Figs. 2 through 7, thethickness of the seam 20 at the point '2! where the two felledcross-seams l3 meet and are interfolded is equal to sixteen. timesthethl-ckness of a single fabric section-. 22,Whereas1the thickness ofthe seam where there are no cross-seams, is only four times that of asingle section. This improved presser means,-in the embodiment shown,includes tandem-connected feet pivotally mountedin. an improvedadvantageous manner, and .yieldably. held in engagement with the work ina novelway whereby they function to insure uniform feeding of the workpast the needles l4.

As shown in Figs. 1 and. 2, the head I 3 has axially movablethereinbetween extended andv retracted positions, a. presser bar 23which is non-rotatable and yieldably urged toward the work-supportingarm "l2 to extendedposition by a helical coil sprin 24. The lowerportion of the barl23extends adjacent to the needles l4, and carri'es'atits end a bracket 25' having a split-collar 2t" and draft screw 21 bymeans of whichthe bracket is. secured to the bar. Referring to Figs.8an'd 9,'the "body of the bracket 25constitutes ayoke i 28 having a pairof depending lugs 29"which'are apertured to pivotally carry a pair ofrocker arms 30' at the centers thereof, saidarms being pierced and"threaded to receive shouldered pivot screws 3| for this purpose. Therocker arms 30 pivotally carry at their forward ends a front presserfoot 32, and attheir rear ends arear presser foot 33, said ends of thearms 'being'apertured to receive respectively shoulderedpivot screws 34and 35 which are in turn threaded into -upstanizling ears 36'of'thefrontfoot andthebodyofthe rear foot.

'The front presser foot'32 has'a body '3'L the underside 38 of whichconstitutes asubs'tantially planar work-engagin surface, saidbodyha'ving needle apertures 39'and an upturned toe 40,th'elatterbeingadapted to guide the foot "over irregularities, such 'ascross=seams and thelike, in the work.

"For the purpose of guiding the reuse seam 23 which is being sewed, thebody'3'l of the front presser foot has along its sides depending flangesflland '32 respectively, which preferably'extend toa depth theequivalent of three thicknesses of a single fabric section. Thus, asshown 'in Fig. 2;"wh'en a portion of the felled-seam'm which has'nocross-seams is passing'between the foot 32 and theithroatplate I! theflange-el-exten'ds past the side of the roll comprising the upper three'thickne'sses'of the seam, and engagesand guides said side-andthe'fabric section 22. The flange 42 on the'other side of the footdepresses the top fa'bric'sectio'n 22a at points alongside the seam20,'as' seen in Fig. 9, so that the latter is accurately. guided andprevented from having side movement while 'being'sewed. 'Ihe flangeE2'is continued along the un'dersi-deof the toe but tapers off towardthe tip, as shown by the dotted line'42a in Fig. 2. The flange 4| isalso continued along the toe 40 to taper off at-the tip, but it firstdeepens at the point- 43 in order to adequately guide the seam 20 wherea deep rolloocurs, as at thepoint2l showing two'crossseams interfolded.

The underside 44 of the rear-presserfoot33 constitutes a planarwork-engaging surface also adapted to press against theseam 20 and thefront endof said foot has a pair of spaced toes extending forwardlythereof into slots 46 in the rear portion of the foot 32, the under edgeof the toes sloping upward as shown to cause the"foot to rise aboveobstructions such as crossseams and. the like. Spacing is providedbetween :the: adjacent interfitting portions of the feet 32 and -33 sothat-each of the latter is independently pivotally movable on the rockerarms 30 with re- 1 spect to the'other within a predetermined range.

This-range is such that the feet do not interfere with each other asthey pivot and bodily move in individually following irregularities inthe work.

As thus pivotally mounted, the presser feet32 and 33 are adapted toengage and guide the felled seam 20 as it is being sewed by the needlesM, said feet being made to press -firmly against the seam by thespring24 acting on the presser'bar 23.

It will be noted that the three plvotpoints of each rocker armarelocated substantially in a straight line, equi-spaced from the seams2ll,the intermediate pivot being preferably substantially' midway betweentheend pivots to divide the pressure of the spring 2 1 equally-between thefeet. "This results in an important advantage 'Whenjoining seamed'fabricsections, or sections havingoth'er irregularities which'might interferewith uniform feeding of'the sections past the needles. -Ri=ferring toFig.2, when a'felled seam is being sewed at apoint removed fromcrossseams so that the latter do not engage the'presser feet 32 and 33,no feeding problem is encountered since the work-engaging'surfaces'38and-44 of the feet are in'alignment and the three pivot points of therocker armsare equispaced from the seam.

"When cross-seams l9 approach the needles H, as seen in Fig. 3,they'first engage the front presser'foot 32 causing it to pivot and alsobodily lift,'and causing a canting 0f the rocker arms 30, accompanied bya retracting of thejpivot 3| and presser-bar 23. This increases thepressure exerted by the spring 24, and as a result the pressure exertedby the feet 32 and 33 on the work. Dueto the fact that the pivots of therocker arms 30 are initially'equispaced from the seam 20, theinitialretracting movementof the front foot 32 is" substantially perpendicularto the line of feed of the seam, and the subsequent retracting movementof the foot is in such a direction that there is no component opposingthe feed'cf the seam, nor the feeding movement of the feed dogs [5. Asaresult, feeding of the work proceeds'with the least amount ofinterference from the'front'foot. 'If the'center pivot 3| "of the rockerarms were spaced further'from' the work thanthe'corresponding spacing ofthe two end pivots, so that it was higher than same, theinitialretracting movement of the front presser foot would notbeperpendicular to the line of feed of the seam 26, but would have acomponent opposing the feed of same and the feeding movement of the feeddogs I5. 1

Similarly, the location of the center pivot 3|, in line with the endpivots so that all three'are equispaced from the seam 20, reduces'theamount of feed-opposing movement of the rear foot which takes placeduring the retracting movementof thefront foot. By thus eliminating andreducing the forces opposing the feeding movement of the seam20'duringthe interval that the front foot 32 is riding'upand over an obstructionsuch as cross-seams l3 interfoldedas at 2l,"a=mor'e positive and uniformfeed is assured during said interval. It is during thisinterval-that-the sew ing of the interfolded'cross seamstake place', asseen in Figs. 2 through 5. V

As seen in Fig. 4, the front presser'foot 32'has entirely mounted-theinterfolding 2 I of the cross seams l9, and'the needles I4 are stitchingat the center of said interfolding. In'Fig. 5,the needles are completingthe stitching cf-theinterfolding 2|, the front foot 3'2 being canted ata'comparatively sharp angle, and the rear foot 33fbeginning to cant asit starts to mount'the cross seams. At this position the center'pivot 3|is comparatively high and its spacing from the work is-greater than thespacing in Figs. 2 and 3. Now, as the interfolding 2! of the cross-seamsleaves the front foot 32 and passes completely under the rear 'foot33,"Figs; '6 and7 ,"the .latter foot in mounting over the seams moves'in a direction which again has no component opposing the feedof theseam. Thus; theaction of the presser feet androcker arms, as providedabove by the invention, is such as to not interfere withfthe continuedfeeding and sewing of the seam 2il, yet these individually andcollectively function to maintain a pressure on the fabric sections andseam thereof whereby the feed dogs I5 uniformly feedthe'workpast theneedles. Where particularly heavy fabric sections having' felledcross-seams are to be joined, and especially if the cross-seams are fedwith the leading roll of the seam on the top of the work where it willcontact the presser feet; as shown in the figures, the inventionprovides'novel means further regulating the action of the presser feet32 and 33 to insure a positive and uniform feeding of the seam 20. Intheembodiment shown,

this embraces a mechanism for providing the rear presserfoot with apressure component, to be transmittedto the work, that is independent ofthe pressure supplied by the bar 23 and functions to supplement saidlatter pressure in a" manner to maintain control at'all times of theseam being sewed. A

Referring to Fig. 1, the bridge portion 13 of the machine is providedwith a stud l3b on which is mounted a rocker 4! having an arm 41a.Secured to the arm 41a is an extension 41b projecting toward the presserbar 23 and terminating between the end of the latter and the rearpresser foot 33. The end portion of. the :extension 411) is divided intotwo fingers 49 and'ill, the finger 49 extending closely against theface23a oft-the end of the bar and being adapted to engage same, and thefinger 5'3 being located adjacent the upper surface of the rear foot 33and'having'ade pending boss. 5! carrying a helical coil spring 52extending into a recess 53 in said foot,isee Fig. 7. When the presserfeet 32 and 33 are in extended position engaging the .work 16, and theextension 41b is in lowered position, as in Fig. 2, the finger 49 isspaced an extent from the end face 23a of the bar. and the spring 52 iscompressed and presses down on the rear foot 33 at a point below thepivot thereof to yieldably .hold same horizon-- tally and evenly inengagementwith the'work. Thus the pressure exerted by'the rear presserfoot 33, as supplied by the spring 24' of the' 'presse'r bar isaugmented by the i'ndependent pressure of the spring 52. InFigs. 3a'nd4, showingprogressive stages in the advance of the Work, the spring52*does not change appreciably from the setting OfiEiE. P 2,. but actscontinuously-to ipress idownion the rear foot 33 for supplementing thepressure of the presser bar spring 24. In Fig. 5, where the felled ends2| of the cross-seams begin to engage and move the rear foot 33, thespring 52 is compressed a slightly greater extent. Figs. 6 and '7illustrate still further compression of the spring 52 as therear footmounts and rises over the felled ends 2| of the cross-seams, the latterfigure showing the spring being compressed a maximum amount. As thespring 52 is compressed it exerts a greater pressure on the foot 33, andthe latter on the seam 23, so that the feed dogs 15 encounter greaterpressure and bite more deeply for these conditions, and therefore thelikelihood of slippage occurring is reduced. As a result, this furtherregulation of the presser feet as accomplished byv the spring 52 efiectsa more uniform and positive feeding of the work.

When theypresser. feet and 33 are to be raised from the work IS therocker 41 is turned slightly in acounterclockwise direction by an arml'lc, thus raising the arm 41a and extension 4112 an extent. After. theextension 41b has moved a short distance the finger 49 thereof engagesthe end face 23a of the bar 23, and further movement of the extensioncarries the bar, and the feet 32 and 33 to-their retracted position. Theextension 41b and bar 23.niaybe locked in theirraised or retractedpositions. until the new work is inserted in the machine and the latteris ready for sewing.

For the-purpose pf preventing the front foot 32, when raised orretracted, from eantin in a clockwise direction whereby the toe 43thereof would be loweredand would hamper insertion of new work, a flatspring 54 having a pair of arms 55 is mounted bymeans of a screw 56 onthe rear face Of the yoke 28, the ends of the arms 55 being formed; intoelongate eyes 55a, Fig. '7, which encircle and engage pins 51respectively carried by the ears35 of said front foot. The spring 54 isarrangedto maintain the front foot 32 in a substantially horizontalposition when the latter is retracted, free from the work.

Variations and modifications may be made within the scope of thisinvention and portions of the improvements may be used without others.

I claim:

' 1. A sewing machine having a throat plate; a presser bar; a frontpresser foot and a rear presser foot; means for mounting the presserfeet in tandem on the presser bar to be bodily movable therewith andbetween limits relatively thereto whereby they are positioned underpressure supplied from the presser bar to engage and move independentlyof one another to follow variations in the thickness of'a workpiecepassing over the throat 'plate; and means independent of the presserjbarand applyin pressure to the rear foot, yieldably holding the latter inworx engaging position and providing a force thereon in addition to thatsupplied by the presser bar.

2. 5A sewing machine having a frame; a throat plate; a presser bar; afront presser foot and a rear presser foot; means mounting thepresserfeet. in tandem," and so that eachis pivotally mounted to turnindependently of the other; means for pivotally mounting the mountingmeans on the presser bar whereby the presser feet are bodily movablerelatively thereto between limits and are positioned by pressuresupplied from the presser bar to engage and move independently of oneanother to follow variations in the thickness of a workpiece passingover the throat plate; and yieldable meansmounted on the frameand bear:-

ing upon theirear presser foot, operating :independently of thepresser-bar, for yieldablyholding the foot in'work-engaging position:whereby the total feeding pressure exerted on the workpiece has .acomponent independent :f .the pressure variations resulting frommovement of the presser bar :due to rising'and falling of the frontfoothin traversing a cross-seam.

3. The invention as defined in claimv2xin whic the. independentyieldable holding means i for 113116 rear foot comprisesa springpressing onttheyfoot at-a point between its pivotal axis and its workengaging surface along a line normal to said surface when the foot isengaging a workpiece whereby the pressure ofsaid foot on the workpiecedue to the spring tends to;distribute itself evenly over thework-engaging surface.

4. A sewing machine having a throat'plate; a'presser bar movably mountedon themachine frame adjacent the throat plate to have a predeterminedline of movement intersecting the plane of feed of the work, andbeingyieldably urged toward an extended position close to the throatplate; a front presser foot and a rear presser foot'each having planarwork-engaging surfaces: a link mounting the presser feet in tandem bypivots located substantially equidistant from their respectivework-engaging surfaces, said feet having their juxtaposed portionsdisconnected and-provided with clearance therebetween whereby the feetare free for independent purely rotative movement with respect to oneanother, and the link being pivoted on the prerser bar-at a pointaligned with and intermediate the pivots 'of the presser feet wherebywhen the presser bar is in extended position said feet under yieldingpressure supplied from the'bar so engage a workpiece that all the pivotsof the link are substantially equi-spaced from the line of feed, andwhereby movement of the front foot away from the surface of the'throatplate due to engagement of said foot with a cross-seam has no componentopposin the feed of the work; and yieldable means independent of thepresser bar, engaging the rear foot to yieldably hold the latter inwork-engagin position and exert a 'force thereon in addition to thatsupplied by the presser bar.

5. A sewing machine having a, throat plate; a

presser bar; a front presser foot and a rear presser foot; means formounting the presser feet in tandem on the presser bar to be bodilymbvable therewith and between limits'relatively thereto whereby they arepositioned by pressure supplied from the presser bar :to engage andindividually move to follow variations in the thickness of a workpiecepassing over the throat plate; means functioning independently of thepresser bar and bearing upon the rear foot for yieldably holding thelatter in Work-engaging position whereby the total feeding pressureexerted on the workpiece has a component independent of the pressurevariations resulting from movement of the presse'r bar due to rising andfalling of the front foot 'in traversing a cross-seam; andmeansforreleasing the independent yieldable holding means for the rearfoot, and for moving the presser bar to retract the presser feet wherebya work-piece may be removed from under same.

6 A sewing machine having a throat plate; a presser bar; a front presserfoot and a rear presser foot; means for mounting the presser feet intandem on the presser bar to be bodily movable therewith and betweenlimits relatively thereto whereby they are positioned byipressuresuppliedffrom the .presser libar tmengage and m dividuallymove-to'followvariations in the thickness of: atworkpiecepassing overthe throat plate; means i functioning independently of the presserbar-and engaging the rear foot for yieldably holding the latter inwork-engaging position wherebythe total feeding pressure exerted :on theworkpiece *hasi-a1component independent of the pressure variationsresulting from movement of the presser-bardue to rising and falling ofthe" front 'foot in -.traversing a cross-seam; and means :for releasingthe independent yield-able holdingmeans forthe rear foot and for-movingthe-presser bar to retract the presser feet wherebya workpieceymay be'removed;from under same, said sfirstenamed means including-a leverconnected to-.the holding means and a lug adapted: toengage thegpresser'bar, and connectedwith saidlever.

"'7. In a sewing machine; theacombinationof; a work .tablepa presser barmounted'adjacent the machine-needle for predetermined extending'andretracting movement with respect to the work table;;theline-of'saidmovementextendin at an angle-with respect to the line offeed'of the work; means for yieldably holding the presser barinextendedposition; afront presser foot and azrear-presser footreach having;planar workengaging surfaces; a link having pivots at its ends formounting thepresser feet in tandem, said pivots'being locatedsubstantially equidistant fromtherespective work-engaging surfacesoftthe feet, saidfeet-being rotatable independently of each --other,said link being pivoted-at its center on the-presser bar so that allpivots are in alignment-andzso that thepresser feet, under pressuresupplied'by said yieldin means, engage a workpiece whereby'all pivots ofthe link are substantiallyiequispacedafrom the line of feed, andwhereby-movementof thefront foot away from the'surface of theworktableldue toenaeementiofsaid footwith a cross-seam has no componentopposing the feed-of the work; means cooperable :withrboth-plan-arwork-engaging surfaces-of the feet for. feeding a workpiece past themachine needle; a spring functioning independcntly'ofx-th'epresser-bar'disposed between an arm mounted on the" machine and the rearpresser foot and engaging. the-latter at a point between the-pivotandwork-engaging surface thereof, foryieldablyi holding said foot inwork-engaging position;'-and-meansforyreleasing the spring andretractingnthe presser-bar to move both presser feetawav from the worktable whereby a workpiece-may be removed-from betweensaid feeding meansand-feet.

"8. :A-sewing machine-having a'frame; a throat plate; apresserbaryafront presser foot and a rearipresser: foot;. means-pivotally mountingthe presser "f-eet.;in tandem, and so that each is mounted torturnindependently 'of'the other; meansfor .rpivotally mounting the mountingmeans .onthe presser bar whereby the presser feet are "bodily nmovablerelatively thereto between'limits and are positioned by pressuresupplied from the-presser bar to engage and move independently ;of oneanother to follow variations in the thickness of'a workpiece passingover the throat plate; and yieldable means mounted on" the; frame "andapplying pressure to the rear :presser foot, operating independently ofthe presser 'bargfor yieldably holding the foot in work-engagingmositiouwherebythe total feed- .ing pressure-exerted on the workpiece'has a componentindependentofthe'pressure variations re- 9 10 Selting frommovement of the presser bar due to UNITED STATES PATENTS nsmg and fallmgof the front foot 1n traverslng a cross-seam, the pivotal mounting ofthe rear Number Name Date presser foot being located substantiallyvertical- 617,751 Laskey Jan. 17, 1899 1y above the point of applicationof pressure to 5 8 ,399 -D5 1 1935 said rear foot by the yieldablemeans. 2,916,354 k an Oct. 8, 1935 FRANCIS P. TAMBURRO. 2,147,128 SailerFeb. 14, 1939 2,156,535 Kucera, May 2, 1939 REFERENCES CITED 2,340,647Cu'mfer F b. 1, 1944 The following references are of record in the 10file of this patent:

